Nasiruddin Haqqani Was Son of Insurgent Group's Founder, Brother of Day-to-Day Chief

ISLAMABAD—A top leader of the Haqqani terrorist network in Afghanistan was gunned down in Pakistan's capital, dealing a major blow to the insurgent group behind some of the most brazen attacks on Afghan and U.S. targets in recent years.

Nasiruddin Haqqani was the son of the movement's founder, Jalaluddin Haqqani, and the brother of its day-to-day chief, Sirajuddin Haqqani. All three are designated "global terrorists" by the U.S. "His death has an important impact not only on the Haqqani family, but also on...